Polymerized olefin substituted succinic acid esters



United States Patent Ofice 3,381,022 Patented Apr. 30, 1968 3,381,022POLYMERIZED OLEFIN SUBSTITUTED SUCCINKC ACID ESTERS William M. Le Suer,Cleveland, Ohio, assignor to The gubrizol Corporation, Wicklifie, Ohio,a corporation of bio No Drawing. Continuation of application Ser. No.274,905, Apr. 23, 1963. This application July 22, 1966, Ser. No. 567,320

18 Claims. (Cl. 260-4048) ABSTRACT OF THE DISCLOSURE Ester derivativesof a hydrocarbon-substituted succinic acid wherein the hydrocarbonsubstituent contains at least about 50 aliphatic carbon atoms, thesubstituent being further characterized by having no more than about 5%olefinic linkages therein based on the total number of car-bon-to-carboncovalent linkages in the substituent. The esters include the acidicesters, diesters, and metal salt esters wherein the ester moiety isderived from monohydric and polyhydric alcohols, phenols, and naphthols.These esters are useful as additives in lubricating com positions,fuels, hydrocarbon oils, and power transmitting fluids as well as beingplasticizers, detergents, antirust agents, and emulsifiers.

This is a continuation of application Ser. No. 274,905 filed Apr. 23,1963, now abandoned.

This invention relates to novel compositions of matter and processes forpreparing the same. In a more particular sense this invention relates tocompositions useful as plasticizers, detergents, anti-rust agents,emulsifiers, and additives in lubricating compositions, fuels,hydrocarbon oils, and power transmitting fluids.

Deterioration of lubricating oils, especially mineral oils, has been agreat concern in the formulation of lubricating compositions for use ininternal combustion engines, transmissions, gears, etc. Deterioration ofthe oil results in the formation of products which are corrosive to themetal surfaces with which the oil comes into contact. It also results inthe formation of products which agglomerate to form sludgeandvarnish-like deposits. The deposits cause sticking of the moving metalparts and obstruct their free movement. They are a principal cause ofmalfunctioning and premature break-down of the equipment which the oillubricates.

It is known that water is a common contaminant in the crankcaselubricant of an engine. It may result from the decomposition of thelubricating oil or come from the combustion chamber as a blow-by productof the burning of the fuel. The presence of water in the lubricant seemsto promote the deposition of a mayonnaiselike sludge. This type ofsludge is more objectionable because it clings tenaciously to metalsurfaces and is not removed by oil filters. If the engine is operatedunder conditions such that the crankcase lubricant temperature iscontinuously high the water will be eliminated about as fast as itaccumulates and only a very small amount of the mayonnaise-like sludgewill be formed. On the other hand, if the crankcase lubricanttemperature is intermittently high and low or consistently low the waterwill accumulate and a substantial quantity of the mayonnaiselike sludgewill be deposited in the engine.

High operating temperatures are characteristic of an engine that is runconsistently at a relatively high speed. However, where an automobile isused primarily for trips of short distance such as is characteristic ofurban, home to work use, a significant portion of the operation occursbefore the engine has reached its optium high temperature. An idealenvironment thus obtains for the accumulation of water in the lubricant.In this type of operation the problem of mayonnaise-like sludge has beenespecially troublesome. Its solution has been approached by the use inthe lubricant of detergents such as metal phenates and sulfonates whichhave been known to be etfective in reducing deposits in engines operatedprimarily at high temperatures. Unfortunately, such known detergentshave not been particularly effective in solving the problems associatedwith low temperature operation particularly those problems which areassociated with crankcase lubricants in engines operated at low orintermittently high and low temperatures.

It is accordingly a principal object of this invention to provide novelcompositions of matter.

It is also an object of this invention to provide compositions which aresuitable for use as additives in hydrocarbon oils.

It is also an object of this invention to provide compositions which areeffective as additives in lubricating compositions.

It is another object of this invention to provide compositions effectiveas detergents in lubricating compositions intended for use in enginesoperated at low or intermittently high and low temperatures.

It is another object of this invention to provide a process of preparingadditives useful as additives in hydrocarbon oils and lubricatingcompositions.

It is another object of this invention to provide lubricatingcompositions.

It is further an object of this invention to provide fuel compositions.

These and other objects are attained in accordance with this inventionby means of an ester of a substantially saturatedhydrocarbon-substituted succinic acid wherein the substantiallyhydrocarbon substituent has at least about 50 aliphatic carbon atomssaid ester being other than one having a nitrogen atom attached directlyto a succinic radical. A critical aspect of this invention is the sizeand the chemical constitution of the substantially hydrocarbonsubstituent of the succinic radical. Thus, only the esters ofsubstituted succinic acids in which the substituent is substantiallysaturated and has at least about 50 aliphatic carbon atoms arecontemplated as being within the scope of this invention. This lowerlimit for the size of the substituent is based upon a consideration notonly of the oil solubility of the esters but also of their effectivenessin applications contemplated by this invention.

The substantially hydrocarbon substituent of the succinic radical maycontain polar groups, provided, however, that the polar groups are notpresent in proportions sutficiently large to alter significantly thehydrocarbon character of the substituent. The polar groups areexemplified by the chloro, bromo, keto, ether, aldehyde, nitro, etc. Theupper limit with respect to the portion of such polar groups in thesubstituent is approximately 10% based on the weight of the hydrocarbonportion of the substituent.

The sources of the substantially hydrocarbon substituent includeprincipally the high molecular weight substantially saturated petroleumfractions and substantially saturated olefin polymers, particularlypolymers of monoolefins having from 2 to 30 carbon atoms. The especiallyI useful polymers are the polymers of 1-mono-olefins such as ethylene,propene, l-butene, isobutene, l-hexene, locetene, 2-methyl-l-heptene,3-cyclohexyl-l-butene, and 2- methyl-S-propyl-l-hexene. Polymers ofmedial olefins, i.e.. olefins in which the olefinic linkage is not atthe terminal position, likewise are useful. They are illustrated by 2-butene, 3-pentene, and 4-octene.

Also useful are the interpolymers of the olefins such as thoseillustrated above with other interpolymerizable olefinic substances suchas aromatic olcfins, cyclic olefins, and polyolefins. Suchinterpolyrners include, for example, those prepared by polymerizingisobutene with styrene: isobutene with butadiene; propene with isoprene;ethylene with piperylene; isobutene with chloroprene; isobutene withp-rnethyl styrene; l-hexene with 1,3-hexadiene; l-octene with l-hexene;l-heptene with l-pentene; 3' methyl-l-butene with l-octene;3,3-dimethyl-l-pentene with l-hexene; isobutene with styrene andpiperylene; etc.

The relative proportions of the mono-olefins to the other monomers inthe interpolymers influence the stability and oil-solubility of thefinal products derived from such interpolymers. Thus, for reasons ofoil-solubility and stability the interpolymers contemplated for use inthis invention should be substantially aliphatic and substantiallysaturated, i.e., they should contain at least about 80%, preferably atleast about 95 on a weight basis, of units derived from the aliphaticmono-olefins and no more than about of olefinic linkages based on thetotal number of carbon-to-carbon covalent linkages. In most instances,the percentage of olefinic linkages should be less than about 2% of thetotal number of carbon-to-carbon covalent linkages.

Specific examples of such interpolyrners include the copolymer of 95%(by weight) of isobutene with 5% of styrene; the terpolymer of 98% ofisobutene with 1% of piperylene and 1% of chloroprene; the terpolymer of95 of isobutene with 2% of l-butene and 3% of lhexene; the terpolymer of80% of isobutene with of l-pentene and 10% of l-octene; the copolymer of80% of lhexene and of l-heptene; the terpolyrner of 90% of isobutenewith 2% of cyclohexene and 8% of propene; and the copolymer of 80% ofethylene and 20% of propene.

Another source of the substantially hydrocarbon radical comprisessaturated aliphatic hydrocarbons such as highly refined high molecularweight white oils or synthetic alkanes such as are obtained byhydrogenation of high molecular weight olefin polymers illustrated aboveor high molecular Weight olefinic substances.

The use of olefin polymers having molecular Weights of about 700-5000 ispreferred. Higher molecular weight olefin polymers having molecularweights from about 10,000 to about 100,000 or higher have been found toimpart viscosity index improving properties to the final products ofthis invention. The use of such higher molecular weight olefin polymersoften is desirable.

The esters of this invention are those of the above-described succinicacids with hydroxy compounds which may be aliphatic compounds such asmonohydric and polyhydric alcohols or aromatic compounds such as phenolsand naphthols. The aromatic hydroxy compounds from which the esters ofthis invention may be derived are illustrated by the following specificexamples: phenol, beta-naphthol, alpha-naphthol, cresol, resorcinol,catehol, p,p-dihydroxybiphenyl, 2-chlorophenol, 2,4-dibutylphenol,propene tetramer-substituted phenol, didodecylphenol, 4,4-methylene-bis-phenol, alpha-decyl-beta-naphthol, polyisobutene(molecularweight of 1000)-substituted phenol, the condensation product ofheptylphenol with 0.5 mole of formaldehyde, the condensation product ofoctylphenol with acetone, di(hydroxyphenyl)oxide,di(hydroxyphenyl)sulfide, di(hydroxyphenyl)disulfide, and4-cyclohexylphenol. Phenol and alkylated phenols having up to threealkyl substitutents are preferred. Each of the alkyl substitutents maycontain 100 or more carbon atoms.

The alcohols from which the esters may be derived preferably contain upto about 40 aliphatic carbon atoms. They may be monohydric alcohols suchas methanols, ethanol, isooctanol, dodecanol, cyclohexanol,cyclopentanol, behenyl alcohol, hexatriacontanol, neopentyl alcohol,isobutyl alcohol, benzyl alcohol, betaphenylethyl alcohol,Z-methylcyclohexanol, beta-chloroethanol, monomethyl ether of ethyleneglycol, monobutyl ether of ethylene glycol, monopropyl ether ofdiethylene glycol, monododecyl ether of triethylene glycol, mono-oleateof ethylene glycol, monostearate of diethylene glycol, sec-pentylalcohol, tert-butyl alcohol, 5- bromo-dodecanol, nitro-octadecanol anddioleate of glycerol. The polyhydric alcohols preferably contain from 2to about 10 hydroxy radicals. They are illustrated by, for example,ethylene glycol, diethylene glycol, triethylene glycol, tetraethyleneglycol, dipropylene glycol, tripropylene glycol, clibutylene glycol,tributylene glycol, and other alkylene glycols in which the alkyleneradical contains from 2 to about 8 carbon atoms..0ther useful polyhydricalcohols include glycerol, mono-oleate of glycerol, monostearate ofglycerol, rnonomethyl ether of glycerol, pentraerythritol,9,10-dihydroxy stearic acid, methyl ester of 9,10-dihydroxy stearicacid, 1,2-butancdiol, 2,3-hexancdiol, 2,4-hexanediol, pinacol,erythritol, arabitol, sorbitol, mannitol, 1,2'cyclohexanediol, andXylene glycol. Carbohydrates such as sugars, starches, celluloses, etc.,likewise may yield the esters of this invention. The carbohydrates maybe exemplified by a glucose, fructose, sucrose, rhamnose, mannose,glyceraldehyde, and galactose.

An especially preferred class of polyhydric alcohols are those having atleast three hydroxy radicals, some of which have been esterified with amonocarboxylic acid having from about 8 to about 30 carbon atoms such asoctanoic acid, oleic acid, stearic acid, linoleic acid, dodecanoic acid,or tall oil acid. Examples of such partially esterified polyhydricalcohols are the mono-oleate of sorbitol, distearate of sorbitol,mono-oleate of glycerol, rnonostearate of glycerol, di-dodecanoate oferythritol.

The esters of this invention may also be derived from unsaturatedalcohols such as allyl alcohol, cinnamyl alcohol, propargyl alcohol,1-cyclohexene-3-ol, an oleyl alcohol. Still other classes of thealcohols capable of yielding the esters of this invention comprises theether-alcohols and amino-alcohols including, for example, theoxyalkylene-, oxy-arylene-, amino-alkylene, andamino-arylcue-substituted alcohols having one or more oxy-alkylene,amino-alkylene or amino-arylene oxy-arylene radicals. They areexemplified by Cellosolve, carbitol, phenoxyethanol,heptylphenyl-(oxypropylene) -H, octyl-(oxyethylene) -H,phenyl-(oxyoctylene) -l-I, m0no(heptylphenyl-oxypropylene)substitutedglycerol, poly(styrene oxide), amino-ethanol, B-amino ethyl-pentanol,di(hydroxyethyl)amine, p-aminophenol, tri(hydroxypropyl)amine,N-hydroxyethyl ethylene diamine, N,N,N',N-tetrahydroxytrimethylenediamine, and the like. For the most part, the ether-alcohols having upto about 150 oxy-alkylene radicals in which the alkylene radicalcontains from 1 to about 8 carbon atoms are preferred.

The esters of this invention may be di-esters of succinic acids oracidic esters, i.e., partially esterified succinic acids; as well aspartially esterified polyhydric alcohols or phenols, i.e., esters havingfree alcoholic or phenolic hydroxyl radicals. Mixtures of theabove-illustrated esters likewise are contemplated within the scope ofthe inventiOn.

The esters of this invention may be prepared by one of several methods.The method which is preferred because of convenience and superiorproperties of the esters it produces, involves the reaction of asuitable alcohol or phenol with a substantially hydrocarbon-substitutedsuccinic anhydride. The esterification is usually carried out at atemperature above about C., preferably between C. and 300 C.

The water formed as a by-product is removed by distillation as theesterification proceeds. A solvent may be used in the esterification tofacilitate mixing and temperature control. It also facilitates theremoval of water from he reaction mixture. The useful solvents includexylene, toluene, diphenyl ether, chlorobenzene, and mineral oil.

The esters of this invention likewise may be obtained by the reaction ofa substituted succinic acid or anhydride The esterification isillustrated by the reaction of ethylene glycol with a substitutedsuccinic anhydride as represented by the equations below. with anepoxide or a mixture of an epoxide and water.

0 A. R-oH--il R-orr-ii-0-c2InoH 0 HOC2H4OH lH2COH CHE-C II (I) wherein Ris a substantially hydrocarbon radical having at least about 50aliphatic carbon atoms. It will be readily appreciated that the aboveequations are merely illus trative. Other products not represented byFormulas I, II, and III may be formed. Polymeric esters formed by thecondensation of two or more molecules of each f the succinic acidreactant and the polyhydric alcohol reactant likewise may be formed. Inmost cases the product is a mixture of esters, the precise chemicalcomposition and the relative proportions of which in the product aredifficult to determine. Consequently, the product of such reaction isbest described in terms of the process by which it is formed.

A modification of the above process involves the replacement of thesubstituted succinic anhydride with the corresponding succinic acid.However, succinic acids readily undergo dehydration at temperaturesabove about 100 C. and are thus converted to their anhydrides which arethen esterified by the reaction with the alcohol reactant. In thisregard, succinic acids appear to be the substantial equivalent of theiranhydrides in the process.

The relative proportions of the succinic reactant and the hydroxyreactant Which are to be used depend to a large measure upon the type ofthe product desired and the number of hydroxyl groups present in themolecule of the hydroxy reactant. For instance, the formation of a Suchreaction is similar to one involving the acid or anhydride with aglycol. For instance, the product represented by the structural FormulaI above may be prepared by the reaction of a substituted succinic acidwith one mole of ethylen oxide. Similarly, the product of Formula II maybe obtained by the reaction of a substituted succinic acid with twomoles of ethylene oxide. Other epoxides which are commonly available foruse in such reaction include, for example, propylene oxide, styreneoxide, 1,2-butylene oxide, 2,3-butylene oxide, epichlorohydrin,cyclohexene oxide, 1,2-octylene oxide, epoxidized soya bean oil, methylester of 9,10-epoxy-stearic acid, and butadiene mono-epoxide. For themost part, the epoxides are the alkylene oxides in which the alkyleneradical has from 2 to about 8 carbon atoms; or the epoxidized fatty acidesters in which the fatty acid radical has up to about 30 carbon atomsand the ester radical is derived from a lower alcohol having up to about8 carbon atoms.

In lieu of the succinic acid or anhydride, a substituted succinic acidhalide may be used in the processes illustrated above for preparing theesters of this invention. Such acid halides may be acid dibromides, aciddichlorides, acid monochlorides, and acid monobromides. The substitutedsuccinic anhydrides and acids can be prepared by, for example, thereaction of maleic anhydride with a high molecular weight olefin or ahalogenated hydrocarbon half ester of a succinic acid, i.e., one inwhich only one such as is obtained by the chlorination of an olefinpolyof the two acid radicals is esterified, involves the use of merdescribed previously. The reaction involves merely one mole of amonohydric alcohol for each mole of the heating the reactants at atemperature preferably from substituted succinic acid reactant, whereasthe formaabout 100 C. to about 250 C. The product from such tion of adiester of a succinic acid involves the use of two a reaction is analkenyl succinic anhydride. The alkenyl moles of the alcohol for eachmole of the acid. On the group may be hydrogenated to an alkyl group.The anhyother hand, one mole of a hexahydric alcohol may combine with asmany as six moles of a succinic acid to form an ester in which each ofthe six hydroxyl radicals of the alcohol is esterified with one of thetwo acid radicals of the succinic acid. Thus, the maximum proportion ofthe succinic acid to be used with a polyhydric alcohol is determined bythe number of hydroxyl groups present in the molecule of the hydroxyreactant. For the purposes of this invention, it has been found thatesters obtained by the reaction of equi-molar amounts of the succinicacid reactant and hydroxy reactant have superior properties and aretherefore preferred.

In some instances it is advantageous to carry out the esterification inthe presence of a catalyst such as sulfuric acid, pyridinehydrochloride, hydrochloric acid, benzene sulfonic acid, p-toluenesulfonic acid, phosphoric acid, or any other known esterificationcatalyst. The amount of the catalyst in the reaction may be as little as0.01% (by weight of the reaction mixture), more often from about 0.1% toabout 5%.

dride may be hydrolyzed by treatment with Water or steam to thecorresponding acid. Another method useful for preparing the succinicacids or anhydrides involves the reaction of itaconic acid or anhydridewith an olefin or a chlorinated hydrocarbon at a temperature usuallywithin the range from about C. to about 250 C. The succinic acid halidescan be prepared by the reaction of the acids or their anhydrides with ahalogenation agent such as phosphorus tribromide, phosphoruspentachloride, or thionyl chloride. These and other methods of preparingthe succinic compounds are well known in the art and need not beillustrated in further detail here.

Still other methods of preparing the esters of this invention areavailable. For instance, the esters may be obtained by the reaction ofmaleic acid or anhydride with an alcohol such as is illustrated above toform a monoor di-ester of maleic acid and then the reaction of thisester with an olefin or a chlorinated hydrocarbon such as is illustratedabove. They may also be obtained by first esterifying itaconic anhydrideor acid and subsequently 7 reacting the ester intermediate with anolefin or a chlorinated hydrocarbon under conditions similar to thosedescribed hereinabove.

The following examples illustrate the esters of this invention and theprocesses for preparing such esters.

Example 1 A substantially hydrocarbon-substituted succinic anhydride isprepared by chlorinatin g a polyisobutene having a molecular weight of1000 to a chlorine content of 4.5% and then heating the chlorinatedpolyisobutene with 1.2 molar proportions of maleic anhydride at atemperature of 150-220 C. The succinic anhydride thus obtained has anacid number of 130. A mixture of 874 grams (1 mole) of the succinicanhydride and 104 grams (1 mole) of neopentyl glycol is mixed at 240-250C./30 mm. for 12 hours. The residue is a mixture of the esters resultingfrom the esterification of one and both hydroxy radicals of the glycol.It has a saponification number of 101 and an alcoholic hydroxyl contentof 0.2%.

Example 2 The di-methyl ester of the substantiallyhydrocarbonsubstituted succinic anhydride of Example 1 is prepared byheating a mixture of 2185 grams of the anhydride, 480 grams of methanol,and 1000 cc. of toluene at 50-65 C. while hydrogen chloride is bubbledthrough the reaction mixture for 3 hours. The mixture is then heated at60-65 C. for 2 hours, dissolved in benzene. washed with water, dried andfiltered. The filtrate is heated at 150 C./60 mm. to rid it of volatilecomponents. The residue is the defined di-methyl ester.

Example 3 The substantially hydrocarbon-substituted succinic anhydrideof Example 1 is partially esterified with an ether-alcohol as follows. Amixture of 550 grams (0.63 mole) of the anhydride and 190 grams (0.32mole) of a commercial polyethylene glycol having a molecular weight of600 is heated at 240250 C. for 8 hours at atmospheric pressure and 12hours at a pressure of 30 mm. Hg until the acid number of the reactionmixture is reduced to 28. The residue is an acidic ester having asaponification number of 85.

Example 4 A mixture of 926 grams of a plyisobutene-substituted succinicanhydride having an acid number of 121, 1023 grams of mineral oil, and124 grams (2 moles per mole of the anhydride) of ethylene glycol isheated at 50l70 C. While hydrogen chloride is bubbled through thereaction mixture for 1.5 hours. The mixture is then heated to 250 C./ 30mm. and the residue is purified by washing with aqueous sodium hydroxidefollowed by washing with water, then dried and filtered. The filtrate isa 50% oil solution of an ester having a saponification number of 48.

Example 5 A mixture of 438 grams of the polyisobutene-substitutedsuccinic anhydride prepared as is described in Example 1 and 333 gramsof a commercial polybutylene glycol having a molecular weight of 1000 isheated for hours at 150-160 C. The residue is an ester having asaponification number of 73 and an alcoholic hydroxyl content of 0.7%.

Example 6 The acidic ester of Example 3 (250 grams) is neutralizecl bymixing with 11 grams (10% excess on a chemical equivalent basis) ofbarium oxide, grams of methanol, and 267 grams of mineral oil at -60 C.The mixture is then heated to 150 C. to distill off volatile componentsand the residue is filtered. The filtrate is a mineral oil solution of amixed ester-metal salt having a saponification number of 17 and a bariumsulfate ash content of 4.6%.

8 Example 7 A mixture of 645 grams of the substantiallyhydrocarbon-substituted succinic anhydride prepared as is described inExample 1 and 44 grams of tetramethylene glycol is heated at -130 C. for2 hours. To this mixture there is added 51 grams of acetic anhydride(esterification catalyst) and the resulting mixture is heated underreflux at l30l60 C. for 2.5 hours. Thereafter the volatile components ofthe mixture are distilled by heating the mixture to l96270 C./3O mm. andthen at 240 C./0.15 mm. for 10 hours. The residue is an acidic esterhaving a saponification number of 121 and an acid number of 58.

Example 8 A mixted ester-metal salt is prepared as follows. A mixture of1545 grams (1.5 moles) of the substituted succinic anhydride having anacid number of and prepared as is described in Example 1 and 46 grams(0.5 mole) of glycerol is heated at 150 C. for 3 hours whereupon theacid number of the reaction mixture is reduced to 68. It is then heatedat 150-190 C. until the acid number is reduced to 53. To this mixturethere is added portionwise grams (1.63 moles) of barium oxide togetherwith 1500 grams of mineral oil and 50 cc. of water. The resultingmixture is heated to 90 C.- 100 C., diluted with 25 cc. of isopropylalcohol and 100 cc. of benzene (solvent mixture), and heated underreflux for 3 hours. Volatile components are then removed by heating themixture to 160 C./35 mm. and the residue filtered. The filtrate is amineral oil solution of the mixed ester-barium salt having a bariumsulfate content of 5.6%.

Example 9 A mixed ester-metal salt is prepared by the procedure ofExample 8 except that pentaerythritol (51 grams, 0.38 mole) is used inplace of glycerol. The product has a barium sulfate ash content of 4.9%.

Example 10 A mixed ester-metal salt is prepared as follows. A mixture isprepared from 1545 grams (1.5 moles) of a polyisobutene-substitutedsuccinic anhydride having an acid number of 110 and 152 grams (0.19mole) of an etheralcohol prepared by the reaction of a sucrose with 8moles of propylene oxide. The mixture is heated at 139-l80 C. for 3hours whereupon the acid number of the mixture is reduced to 45. It isdiluted with 320 grams of mineral oil and heated at l70195 C. for 3.5hours until the acid number is 42. To this mixture there are added 1180grams of mineral oil, 50 grams of water, 50 cc. of isopropanol, and 128grams (0.83 mole) of barium oxide at 70 C. The resulting mixture isheated at 90105 C. for 3 hours and dried at 158 C. The residue isfiltered. The filtrate is a mineral oil solution of the mixedesterbarium salt having a barium sulfate ash content of 5.6%.

Example 11 A mixture of 456 grams of a polyisobutene-substitutedsuccinic anhydride prepared as is described in Example 1 and 350 grams(0.35 mole) of the monophenyl ether of a polyethylene glycol having amolecular Weight of 1000 is heated at -155 C. for 2 hours. The productis an ester having a saponification number of 71, an acid number of 53,and an alcoholic hydroxyl content of 0.52%.

Example 12 An ester is prepared by heating at the reflux temperature for10 hours a xylene solution of an equi-molar mixture of thepolyisobutene-substituted succinic anhydride of Example 1 and acommercial polystyrene oxide having a molecular weight of 500 whilewater is removed by azeotropic distillation. The mixture is then heatedto 160 C./l8 mm. The residue is an ester having a saponification numberof 67, an acid number of 45, and an alcoholic hydroxyl content of 1.2%.

Example 13 A di-oleyl ester is prepared as follows. A mixture of 1 moleof a polyisobutene-substituted succinic anhydride, 2 moles of acommercial oleyl alcohol, 305 grams of xylene, and 5 grams of p-toluenesulfonic acid (esterfication catalyst) is heated at 150-173 C. for 4hours whereupon 18 grams of water is collected as the distillate. Theresidue is washed with water and the organic layer dried and filtered.The filtrate is heated to 175 C./ 20 mm. and the residue is the definedester.

Example 14 A di-oleyl ester is prepared by the procedure of Example 13except that the substituted succinic anhydride used is prepared by thereaction of a chlorinated petroleum oil having a molecular weight of 800with maleic anhydride.

Example 15 An ether-alcohol is prepared by the reaction of 9 moles ofethylene oxide with 0.9 mole of a polyisobutene-substituted phenol inwhich the polyisobutene substituent has a molecular weight of 1000. Asubstantially hydrocarbonsubstituted succinic acid ester of thisether-alcohol is prepared by heating a xylene solution of an equi-molarmixture of the two reactants in the presence of a catalytic amount ofp-toluene sulfonic acid at 157 C. The ester is found to have asaponification number of 25 and an acid number of 10.

Example 16 A polyhydric alcohol is prepared by copolymerizing equi-molarproportions of styrene and allyl alcohol to a copolymer having amolecular weight of 1150 and containing an average of 5 hydroxylradicals per mole. An ester of this alcohol is prepared as follows. Amixture of 340 grams (0.3 mole) of the alcohol and 1.5 moles of apolyisobutene-substituted succinic anhydride as is prepared in Example 1in 500 grams of xylene is heated at 80 115 C., diluted with mineral oil,then heated to distill off xylene, and filtered. The filtrate is furtheresterfied by heating with propylene oxide (one equivalent per equivalentof the un-esterfied anhydride) at 70150 C. under reflux. The product isdiluted with oil to an oil solution having an oil content of 40% Example17 A substantially hydrocarbon-substituted succinic acid is prepared bychlorinating a polyisobutene having a molecular weight of 50,000 to achlorine content of 3.9%, reacting the chlorinated polyisobutene withmaleic anhydride to form a substituted succinic anhydride having an acidnumber of 20, and hydrolyzing the anhydride by treatment with steam at102133 C. to the corresponding acid. A mixture of 315 grams of the acid(0.06 mole) and 10 grams (0.17 mole) of propylene oxide is heated at90102 C. for 1 hour. The residue is then heated at 1001 10 C./1 mm. Theabove treatment with propylene oxide is repeated twice. The finalproduct is found to have a saponification number of 20.

Example 18 An ester of an ether-alcohol is prepared by heating a toluenesolution of an aqui-molar mixture of the substantiallyhydrocarbon-substituted succinic anhydride of Example 1 and a commercialpolyethylene glycol at 97- 102 C. for 6 hours and then at 110 C./16 mm.The ester has a saponification number of 37 and an acid number of 26.

Example 19 A di-(hydroxypropy1)ester is prepared as follows: propyleneoxide (58 grams, 1 mole) is added dropwise to a mixture of 0.5 mole ofthe substantially hydrocarbonsubstituted succinic anhydride of Example 1and 8 grams (0.1 mole, esterification catalyst) of pyridine at 90 C. Themixture is heated at reflux for 1 hour, diluted with 400 grams ofmineral oil and heated to 170/40 mm. The residue is filtered. Thefiltrate is a 40% mineral oil solution of the defined ester.

Example 20 An ester is obtained by heating a mixture of 525 grams of thesubstantially hydrocarbon-substituted succinic anhydride of Example 1,422 grams of butyl 9,10-epoxystearate, and 9.5 grams of pyridine(esterification catalyst) at 200 C. for 2.5 hours. The mixture isdiluted with 630 grams of mineral oil and heated to 210 C./20 mm. Theresidue is a mineral oil solution of the ester having a saponificationnumber of 70, an acid number of 1.4, and an alcoholic hydroxyl contentof 0.3%.

Example 21 An ester is prepared by the procedure of Example 20 exceptthat the butyl 9,10-epoxystearate is replaced with dipentene di-epoxide(0.64 mole per mole of the anhydride used). A 40% mineral oil solutionof the ester obtained has a saponification number of 54 and an acidnumber of 0.4.

Example 22 A partial ester of sorbitol is obtained by heating a xylenesolution containing the substantially hydrocarbon substituted succinicanhydride of Example 1 and sorbitol (0.5 mole per mole of the anhydride)at 155 C. for 6 hours while water is removed by azeotropic distillation.The residue is filtered and the filtrate is heated at C./1l mm. todistill off volatile components. The residue is an ester having asaponification number of 97 and an alcoholic hydroxyl content of 1.5%.

Example 23 An ester is obtained by heating an aqui-molar mixture ofdibutyl itaconate and chlorinated polyisobutene having a chlorinecontent of 4.7% and a molecular weight of 700 at 220 C. for 7 hours andthen at 200 C./ 3 mm. The residue is filtered. The filtrate is the esterhaving a saponification number of 74.

Example 24 An ester is obtained by the further esterification ofsorbitol mono-oleate with a substituted succinic anhydride as follows: amixture of 126 grams of sorbitol mono-oleate, 770 grams of thesubstantially hydrocarbon substituted succinic anyhydride of Example 1,588 grams of mineral oil, 500 cc. of xylene and 9 grams of p-toluenesulfonic acid (esterification catalyst) is heated at 140 C. while wateris removed by azeotropic distillation. The residue is washed with waterand dried at 150 C./20 mm. The product is a 40% mineral oil solution ofan ester having a saponification number of 68.

Example 25 An ester is obtained by the procedure of Example 24 exceptthat soribtol tri-oleate (272 grams) is used in place of sorbitanmono-oleate. The product is a 40% oil solution of the ester having asaponification number of 79.

Example 26 A substantially hydrocarbon-substituted succinic anhydride isprepared as is described in Example 1 except that a copolymer of 90weight percent of isobutene and 10 weight percent of piperylene having amolecular weight of 66,000 is used in lieu of the polyisobutene used.The anhydride has an acid number of 22. An ester is prepared by heatinga toulene solution of an equi-molar mixture of the above anhydride and acommercial alkanol consisting substantially of C1244 alcohols at thereflux temperature for 7 hours while water is removed 1 it by azeotropicdistillation. The residue is heated at 150 C./ 3 mm. to remove volatilecomponents and diluted with mineral oil. A 50% oil solution of the esteris found to have a saponification number of 17 and an acid number of5.7.

Example 27 A substantially hydrocarbon-substituted succinic anhydridehaving an acid number of is obtained from maleic anhydride and acopolymer of 90 Weight percent of isobutene with 10 Weight percent ofpiperylene having a molecular weight of 20,000. An ester of the aboveanhydride with allyl alcohol is prepared by heating a toluene solutioncontaining the anhydride and allyl alcohol (4 moles per mole of theanhydride) in the presence of a catalytic amount of p-toluene sulfonicacid at 110- 125 C. The residue is then treated with calcium hydroxideand filtered. The solvent is then removed from the filtrate and theresidue is dissolved in a mineral oil to make up a 50% oil solution.

Example 28 An ester is obtained by the procedure of Example 24 exceptthat 234 grams of a poly(oxyethylene) substituted sorbitol mono-oleatehaving a molecular Weight of 234 is used in place of sorbitolmono-oleate. The ester has a saponification number of 53.

The esters of this invention are useful for a Wide variety of purposes,as pesticides, plasticizers, rust-inhibiting agents,corrosion-inhibiting agents, extreme pressure agents, detergents, etc.

A principal utility of the esters is as additives in lubricants. It hasbeen discovered in accordance with this invention that when used forsuch purpose the esters depend for their effectiveness upon the size ofthe substantially hydrocarbon substitutent in the succinic radical. Moreparticularly, it has been found that esters in which the substantiallyhydrocarbon substituent contain more than about 50 aliphatic carbonatoms are effective to impart detergent properties to a lubricant,especially under low temperature, or intermittently high and lowtemperature, service conditions. It has been further found that thedetergent properties of the esters diminish sharply when the size ofthis substituent is less than about 50 aliphatic carbon atoms, so thatesters having less than about aliphatic carbon atoms in this substituentare relatively ineffective for the purposes of this invention.

The lubricating oils in which the esters of this invention are useful asadditives may be of synthetic, animal, vegetable, or mineral origin.Ordinarily, mineral lubricating oils are preferred by reason of theiravailability, general excellence, and low csot. For certainapplications, oils belonging to one of the other three groups may bepreferred. For instance, synthetic polyester oils such as didodecyladipate and di-Z-ethylhexyl sebacate are often preferred as jet enginelubricants. Normally, the lubricating oils preferred will be fluid oilsranging in viscosity from about Saybolt Universal Seconds at 100 F. toabout 200 Saybolt Universal Seconds at 210 F.

The concentration of the esters as additives in lubricants usuallyranges from about 0.01% to about 10% by weight. The optimumconcentration for a particular application depends to a large extentupon the type of service to which the lubricants are to be subjected.Thus, for example, lubricants for use in gasoline engines may containfrom about 0.5 to about 5% of the additive Whereas lubricatingcompositions for use in gears and diesel engines may contain as much as10% or even more of the additive This invention contemplates also thepresence of other additives in the lubricating compositions. Suchadditives include, for example, supplemental detergents of theashcontaining type, viscosity index improving agents, pour pointdepressing agents, anti-foam agents, extreme pressure agents,rust-inhibiting agents, and supplemental oxidation andcorrosion-inhibiting agents.

The ash-containing detergents are exemplified by oilsoluble neutral andbasic salts of alkali or alkaline earth metals with sulfonic acids,carboxylic acids, or organic phosphorus acids characterized by at leastone direct carbon-to-phosphorus linkage such as those prepared by thetreatment of an olefin polymer (e.g., polyisobutene having a molecularweight of 1000) with a phosphorizing agent such as phosphorustrichloride, phosphorus heptasulfide, phosphorus pentasulfide,phosphorus trichloride and sulfur, white phosphorus and a sulfur halide,or phosphorothioic chloride. The most commonly used salts of such acidsare those of sodium, potassium, lithium, calcium, magnesium, strontium,and barium.

The term basic salt is use to designate the metal salts wherein themetal is present in stoichiometrically larger amounts than the organicacid radical. The commonly employed methods for preparing the basicsalts involves heating a mineral oil solution of an acid with astoichiometric excess of a metal neutralizing agent such as the metaloxide, hydroxide, carbonate, bicarbonate, or sulfide at a temperatureabout C. and filtering the resulting mass. The use of a promoter" in theneutralization step to aid the incorporation of a large excess of metallikewise is known. Examples of compounds useful as the promoter includephenolic substances, such as phenol, naphthol, alkylphenol, thiophenol,sulfurized alkylphenol, and condensation products of formaldehyde with aphenolic substance, alcohols such as methanol, 2-propanol, octylalcohol, Cellosolve, carbitol, ethylene glycol, stearyl alcohol, andcyclohexyl alcohol; amines such as aniline, phenylenediamine,phenothiazine, phenyl beta-naphthylamine, and dodecylamine. Aparticularly eifective method for preparing the basic salts comprisesmixing an acid with an excess of a basic alkaline earth metalneutralizing agent, a phenolic promoter compound, and a small amount ofwater and carbonating the mixture at an elevated temperature such as 200C.

The preparation of a basic sulfonate detergent is illustrated asfollows: A mixture of 490 parts (by weight) of a mineral oil, parts ofwater, 61 parts of heptylphenol, 340 parts of barium mahogany sulfonate,and 227 parts of barium oxide is heated at 100 C. for 0.5 hour and thento C. Carbon dioxide is then bubbled into the mixture until the mixtureis substantially neutral. The mixture is filtered and the filtrate foundto have a sulfate ash content of 25%.

The preparation of a basic barium salt of a phosphorus acid isillustrated as follows: A polyisobutene having a molecular weight of50,000 is mixed with 10% by weight of phosphorus pentasulfide at 200 C.for 6 hours. The resulting product is hydrolyzed by treatment with Steamat to produce an acidic intermediate. The acidic intermediate is thenconverted to a basic salt by mixing with twice its volume of mineraloil, 2 moles of barium hydroxide and 0.7 mole of phenol and carbonatin-gthe mixtture at 150 C. to produce a fluid product.

The esters of this invention are especially adapted for use incombination with extreme pressure and corrosioninhibiting additives suchas metal dithiocarbamates, xanthates. the Group 11 metalphosphorodithioates and their epoxide adducts, hindered phenols,sulfurized cycloalkanes, di-alkyl-polysulfides, sulfurized fatty esters,phosphosulfurized fatty esters, alkaline earth metal salts of alkylatedphenols, dialkyl phosphites, triaryl phosphites, and esters ofphosphorodithioic acids. Combinations of the esters of this inventionwith any of the above-mentioned additives are especially desirable foruse in lubricants which must have superior extreme pressure andoxidation-inhibiting characteristics.

The Group 11 metal phosphorodithioates are the salts of acids having theformula in which R and R are substantially hydrocarbon radicals. Themetals for forming such salts are exemplified by barium calcium,strontium, zinc, and cadmium. The barium and zinc phosphorodithioatesare especially preferred. The substantially hydrocarbon radicals in thephosphorodithioic acid are preferably low or medium molecular weightalkyl radicals and alkylphenyl radicals, i.e., those having from about 1to about 30 carbon atoms in the alkyl group. Illustrative alkyl radicalsinclude methyl, ethyl, isopropyl, isobutyl, n-butyl, sec-butyl, thevarious amyl alcohols, n-hexyl methylisobutyl carbinyl, heptyl,2-ethylhexyl, diisobutyl, isooctyl, nonyl, behenyl, decyl, etc.Illustrative lower alkylphenyl radicals include butylphenyl, amylphenyl,di-amylphenyl, octylphenyl, etc. Cycloalkyl radicals likewise are usefuland these include chiefly cyclohexyl and the lower alkyl-cyclohexylradicals. Other substantially hydrocarbon radicals likewise are use fulsuch as tetradecyl, octadecyl, eicosyl, butylnaphthyl, hexylnaphthyl,octylnaphthyl, cyclohexylphenyl, naphthenyl, etc. Many substitutedhydrocarbon radicals may also be used, e.'g., chloropentyl,dichlorophenyl, and dichlorodecyl.

The availability of the phosphorodithioic acids from which the Group IImetal salts of this invention are prepared is well known. They areprepared by the reaction of phosphorus pentasulfide with an alcohol orphenol. The reaction involves four moles of the alcohol or phenol permole of phosphorus pentasulfide, and may be carried out within thetemperature range from about 50 C. to about 200 C. Thus the preparationof o,o-di-n hexylphosphorodithioic acid involves the reaction ofphosphorus pentasulfide with four moles of n-hexyl alcohol at about 100C. for about 2 hours. Hydrogen sulfide is liberated and the residue isthe defined acid. The preparation of the zinc or barium salt of thisacid may be eflected by reaction with zinc oxide or barium oxide. Simplymixing and heating these two reactants is sufficient to cause thereaction to take place and the resulting product is sufiiciently purefor the purpose of this invention.

Especially useful Group II metal phosphorodithioates can be preparedfrom phosphorodithioic acids which in turn are prepared by the reactionof phosphorus pentasulfide with mixtures of alcohols. The use of suchmixtures enables the utilization of cheaper alcohols which in themselvesdo not yield oil-soluble phosphorodithioic acids. Thus a mixture ofisopropyl and hexyl alcohols can be used to produce a very effective,oil-soluble metal phosphorodithioate. For the same reason mixtures ofsimple phosphorodithioic (i.e., acids prepared from one alcohol) acidscan be reacted with zinc oxide or barium oxide to produce lessexpensive, oil-soluble salts.

Another class of the phosphorothioate additives contemplated for use inthe lubricating compositions of this invention comprises the adducts ofthe metal phosphorodithioates described above with an epoxide. The metalphosphorodithioates useful in preparing such adducts are for the mostpart the zinc phosphorodithioates. The epoxides may be alkylene oxidesor arylalkylene oxides. The arylalkylene oxides are exemplified bystyrene oxide, pethylstyrene oxide, alpha-methylstyrene oxide,3-betanaphthyl-1,3-butylene oxide, m-dodecylstyrene oxide, andp-chlorostyrene oxide. The alkylene oxides include principally the loweralkylene oxides in which the alkylene radical contains 6 or less carbonatoms. Examples of such lower alkylene oxides are ethylene oxide,propylene oxide, 1,2-butene oxide, trimethylene oxide, tetramethyleneoxide, butadiene Lmonoepoxide, 1,2-hexene oxide, and propyleneepichlorohydrin. Other epoxides useful herein include, for example,butyl 9,10-epoxy-stearate, epoxidized soya bean oil, epoxidized tungoil, and epoxidized copolymer of styrene with butadiene.

The adduct may be obtained by simply mixing the phosphorodithioate andthe epoxide. The reaction is usually exothermic and may be carried outwithin wide temperature limits from about C. to about 200 C.

Because the reaction is exothermic it is best carried out by adding onereactant, usually the epoxide, in small increments to the other reactantin order to obtain convenient control of the temperature of thereaction. The reaction may be carried out in a solvent such as benzene,mineral oil, naphtha, or n-hexane.

The chemical structure of the adduct is not known. More than one mole,sometimes as many as four moles, of the epoxide can be made to combinewith the prosphorodithioate to form products useful herein. However,adducts obtained by the reaction of one mole of the phosphorodithioatewith from about 0.25 mole to about 1 mole of a lower alkylene oxide,particularly ethylene oxide and propylene oxide, have been found to beespecially useful and therefore are preferred.

The lubricating compositions may contain metal detergent additives inamounts usually within the range of from about 0.1% to about 20% byweight. In some applications such as in lubricating marine dieselengines the lubricating compositions may contain as much as 30% of ametal detergent additive. They may contain extreme pressure additionagents, viscosity index improving agents, and pour point depressingagents, each in amounts within the range from about 0.1% to about 10%.

The following examples are illustrative of the lubricating compositionsof this invention: (all percentages are by weight.)

EXAMPLE I SAE 20 mineral lubricating oil containing 0.5% of the productof Example 1.

EXAMPLE II SAE 30 mineral lubricating oil containing 0.75% of theproduct of Example 2 and 0.1% of phosphorus as the barium salt ofdi-n-nonylphosphorodithioic acid.

EXAMPLE III SAE l0W-30 mineral lubricating oil containing 0.4% of theproduct of Example 3.

EXAMPLE IV SAE mineral lubricating oil containing 0.1% of the product ofExample 4 and 0.15% of the zinc salt of an equi-molar mixture ofdi-cyclohexylphosphorodithioic acid and di-isobutyl phosphorodithioicacid.

EXAMPLE V SAE 30 mineral lubricating oil containing 2% of the product ofExample 12.

EXAMPLE VI SAE 20W-30 mineral lubricating oil containing 5% of theproduct of Example 24.

EXAMPLE VII SAE l0W-30 mineral lubricating oil containing 1.5% of theproduct of Example 2 and 0.05% of phosphorus as the zinc salt of aphosphorodithioic acid prepared by the reaction of phosphoruspentasulfide with a mixture of 60% (mole) of p-butylphenol and 40%(mole) of n-pentyl alcohol.

EXAMPLE VIII SAE 50 mineral lubricating oil containing 3% of the productof Example 26 and 0.1% of phosphorus as the calcium salt ofdi-hexylphosphorodithioate.

EXAIMPLE IX SA-E 10W-30 mineral lubricating oil containing 2% of theproduct of Example 2, 0.06% of phosphorus as zincdi-n-octylphosphorodithioate, and 1% of sulfate ash as barium mahoganysulfonate.

EXAMPLE X SAE 30 mineral lubricating oil containing 5% of the product ofExample 10, 0.1% of phosphorus as the zinc 15 salt of a mixture ofequi-molar amounts of di-isopropyl phosphorodithioic acid anddi-n-decylphosphorodithioic acid, and 2.5% of sulfate ash as a basicbarium detergent prepared by carbonating at 150 C. a mixture comprisingmineral oil, barium di-dodecylbenzene sulfonate and 1.5 moles of bariumhydroxide in the presence of a small amount of water and 0.7 mole ofoctylphenol as the promoter.

EXAMPLE XI SAE 10W-30 mineral lubricating oil containing 6% of theproduct of Example 17, 0.075% of phosphorus as zincdi-n-octylphosphorodithioatc, and of the barium salt of an acidiccomposition prepared by the reaction of 1000 parts of a polyisobutenehaving a molecular weight of 60,000 with 100 parts of phosphoruspentasulfide at 200 C. and hydrolyzing the product with steam at 150 C.

EXAMPLE XII SAE mineral lubricating oil containing 2% of the product ofExample 25, 0.075% of phosphorus as the adduct of zincdi-cyclohexylphosphorodithioate treated with 0.3 mole of ethylene oxide,2% of a sulfurized sperm oil having a sulfur content of 10%, 3.5% of apoly-(alkyl methacrylate) viscosity index improvcr, 0.02% of apoly-(alkyl methacrylate) pour point depressant, 0.003% of a poly-(alkylsiloxane) anti-foam agent.

EXAMPLE XIII SAE 10 mineral lubricating oil containing 1.5% of theproduct of Example 14, 0.075% of phosphorus as the adduct obtained byheating Zinc dinonylphosphorodithioate with 0.25 mole of 1,2-hexeneoxide at 120 C., a sulfurized methyl ester of tall oil acid having asulfur content of 6% of a polybutene viscosity index improvcr, 0.005% ofa poly-(alkyl methacrylate) antifoam agent, and 0.5 of lard oil.

EXAMPLE XIV SAE mineral lubricating oil containing 1.5% of the productof Example 2, 0.5% of di-dodecyl phosphite, 2% of the sulfurized spermoil having a sulfur content of 9%, a basic calcium detergent prepared bycarbonating a mixture comprising mineral oil, calcium mahogany sulfonateand 6 moles of calcium hydroxide in the presence of an equi-molarmixture (10% of the mixture) of methyl alcohol and n-butyl alcohol asthe promoter at the reflux temperature.

EXAMPLE XV SAE 10 mineral lubricating oil containing of the product ofExample 9, 0.07% of phosphorus as zinc dioctylphosphorodithioate, 2% ofa barium detergent prepared by neutralizing with barium hydroxide thehydrolyzed reaction product of a polypropylene (molecular weight of2000) with 1 mole of phosphorus pentasulfide and 1 mole of sulfur, 3% ofa barium sulfonate detergent prepared by carbonating a mineral oilsolution of mahogany acid, and a 500% stoichiometrically excess amountof barium hydroxide in the presence of phenol as the promoter at 180 C.,3% of a supplemental ashless detergent prepared by copolymerizing amixture of 95% (weight) of decyl-methacrylate and 5% (weight) ofdiethylaminoethylacrylate.

EXAMPLE XVI SAE 80 mineral lubricating oil containing 2% of the productof Example 20, 0.1% of phosphorus as zinc din-hexylphosphorodithioate,10% of a chlorinated parafiin wax having a chlorine content of 40%, 2%of di-butyl tetrasulfide, 2% of sulfurized dipentene, 0.2% of oleylamide, 0.003% of an anti-foam agent, 0.02% of a pour point depressant,and 3% Of a viscosity index improver.

1 6 EXAMPLE XVH SAE 10 mineral lubricating oil containing 3% of theproduct of Example 2, 0.075 of phosphorus as the zinc salt of aphosphorodithioic acid prepared by the reaction of phosphoruspentasulfide with an equi-molar mixture of n-butyl alcohol and dodecylalcohol, 3% of a barium detergent prepared by carbonating a mineral oilsolution containing 1 mole of sperm oil, 0.6 mole of octylphenol, 2moles of barium oxide, and a small amount of water at 150 C.

EXAMPLE XVIII SAE 20 mineral lubricating oil containing 2% of theproduct of Example 12 and 0.07% of phosphorus as zincdi-n-octylphosphorodithioate.

EXAMPLE XIX SAE 30 mineral lubricating oil containing 3% of the productof Example 14 and 0.1% of phosphorus as zinc di- (isobutylphenyl)-phosphorodithio ate.

EXAMPLE XX SAE 50 mineral lubricating oil containing 2% of the productof Example 15.

EXAMPLE XXI SAE mineral lubricating oil containing 3% of the product ofExample 18 and 0.2% of phosphorus as the reaction product of 4 moles ofturpentine with 1 mole of phosphorus pentasulfide.

EXAMPLE XXII SAE 90 mineral lubricating oil containing 3% of the productof Example 19 and 0.2% of 4,4'-rnethylene-bis (2,6-di-tert-butylphenol)EXAMPLE XXIII SAE 30 mineral lubricating oil containing 2% of theproduct of Example 22 and 0.1% of phosphorus as phenylethyldi-cyclohexylphosphorodithioate.

EXAMPLE XXIV SAE 90 mineral lubricating oil containing 5% of the productof Example 2 and 1% of the calcium salt of the sulfurized phenolobtained by the reaction of 2 moles of heptylphenol with 1 mole ofsulfur.

The above lubricants are merely illustrative and the scope of theinvention includes the use of all of the additives previouslyillustrated as Well as others within the broad concept of this inventiondescribed herein.

The eifectiveness of the esters of this invention as detergent additivesin lubricating compositions is shown by the results in Table I of themodified CRCEX3 engine test (the modification consists of extending thetest period from the specified 96 hours to 144 hours, thus making thetest more severe). The test is recognized in the field as an importanttest by which lubricants can be evaluated for use under relatively lightduty or intermittently high and low temperature service conditions suchas are encountered in the operation of automobiles in urban use. In thistest, the lubricant is used in the crankcase of a 1954 6-cylinderChevrolet Power-glide engine operated for 144 hours under recurringcyclic conditions, each cycle consisting of: 2 hours at engine speed of500 rpm. under no load, oil sump temperature of 125 F., and air:fuelratio of 10.1; and 2 hours at an engine speed of 2500 r.p.m. under aload of 40 brake horsepower, oil sump temperature of 240280 F., and anairzfuel ratio of 16:1. At the end of the test the lubricant is rated interms of (1) the extent of piston filling, (2) the amount of sludgeformed in the engine (rating scale of 80-0, 80 being indicative of nosludge and 0 being indicative of extremely heavy sludge) (3) the totalamount of engine deposits, i.e., sludge and varnish formed in the engine(rating scale of 100-0, 100 being indicative of no deposit and 0 beingindicative of extremely heavy deposits).

The lubricating oil base used in the lubricants tested in a SAE 20mineral lubricating oil.

1. An oil-soluble ester selected from the class consisting of acidicesters, diesters, and mixtures thereof, said esters being esters ofsubstantially saturated polymerized olefin-substituted succinic acid andmonoor polyhydric aliphatic alcohols having up to 40 carbon atoms,wherein the polymerized olefin substituent has at least about 50aliphatic carbon atoms and a molecular weight of about 700 to about5000, having no more than about olefinic linkages based on the totalnumber of carbon-tocarbon covalent linkages in said substituent.

2. An ester according to claim 1 wherein said polymerized olefinsubstituent is polymerized l-mono-olefin substituent.

3. An ester according to claim 2 wherein said l-monoolefin is selectedfrom the class consisting of propene and isobutene.

4. An ester according to claim 1 wherein said polymerized olefinsubstituent is an interpolymerized olefin substituent.

5. An ester according to claim 1 wherein said hydroxy compound is apolyhydric alcohol having up to 40 aliphatic carbon atoms and from 2 toabout hydroxy radicals.

6. An ester according to claim 5 wherein the polyhydric alcohol has atleast 3 hydroxy radicals and is partially esterified with an aliphatichydrocarbon monocarboxylic acid having from 8 to 30 carbon atoms.

7. An ester according to claim 5 wherein said polymerized olefinsubstituent is an interpolymerized olefin substituent.

8. An ester according to claim 5 wherein said polymerized olefinsubstituent is polymerized l-mono-olefin substituent.

9. An ester according to claim 8 wherein said l-monoolefin is selectedfrom the class consisting of propene and isobutene.

10. An ester according to claim 9 wherein said 1- mono-olefin isisobutene.

11. An ester according to claim 10 wherein said polyhydric alcohol isselected from the class consisting of glycerol, pentaerythritol, andsorbitol.

12. An ester according to claim 10 which is an ester of pentaerythritol.

13. An oil-soluble ester selected from the class consisting of acidicesters, diesters, and mixtures thereof of an oxyalkylene ether alcoholhaving up to about 150 oxyalkylene radicals in which the alkyleneradical contains from 1 to about 8 carbon atoms and a substantiallysaturated polymerized olefin-substituted succinic acid wherein thesubstantially saturated polymerized olefin substituent has at leastabout 50 aliphatic carbon atoms and a molecular weight of about 700 toabout 5000 with no more than about 5% olefinic linkages based on thetotal number of carbon-to-carbon covalent linkages in said substituent.

14. An ester according to claim 13 wherein said polymerized olefinsubstituent is polymerized l-mono-olefin substituent.

15. An ester according to claim 14 wherein said 1- mono-olefin isselected from the class consisting of propene and isobutene.

16. An ester according to claim 6 wherein said alcohol is sorbitolmonooleate.

17. An ester according to claim 10 wherein said polyhydric alcohol issorbitol.

18. An ester according to claim 14 wherein said polymerized olefinsubstituent is polymerized isobutene and said oxyalkylene ether alcoholis selected from the class consisting of polybutylene glycol andmonophenyl ether of polyethylene glycol.

References Cited UNITED STATES PATENTS Re. 24,287 3/1957 Smith.

2,883,367 4/1959 Dazzi 26078.4 2,933,468 4/1960 Aldridge et a1. 2602973,255,108 6/1966 Wiese 25232.7 2,469,371 5/1949 Colbeth. 2,903,3829/1959 Berls 117-143 2,973,344 2/1961 Fasce. 3,184,474 5/1965 Catle etal 260485 3,197,409 7/1965 de Vries 252-56 3,219,666 11/1965 Norman etal. 2,294,259 8/ 1942 Van Peski. 2,561,232 7/1951 Rudel. 2,575,19511/1951 Smith. 2,575,196 11/1951 Smith. 2,647,872 8/ 1953 Peterson 252282,682,489 6/1954 Von Fuchs 25256 2,825,723 3/1958 Ballauf et a1. 26094.92,944,025 7/ 1960 Verdol 252-5 1.5 3,037,051 5/1962 Stromberg 2604853,047,504 7/ 1962 Peters et al 2525 6 3,057,892 10/1962 DeGrotte.3,086,043 4/1963 Gaertner 260485 3,155,686 11/1964 Prell et a1.3,062,745 11/1962 Gaynor 25256 3,117,091 1/1964 Staker 25256 2,999,8689/ 1961 Phillips 260485 FOREIGN PATENTS 793,07 0 4/ 1958 Great Britain.

LORRAINE A. WEINBERGER, Primary Examiner.

I. R. PELLMAN, T. L. GALLOWAY,

Assistant Examiners.

